1. Field of the Invention
The present invention relates to a multilayer ceramic capacitor. Further, the present invention relates to a method for manufacturing a multilayer ceramic capacitor.
2. Description of the Related Art
A multilayer ceramic capacitor as a typical ceramic electronic component generally includes a multilayer body having a plurality of laminated dielectric layers and a plurality of internal electrodes arranged along interfaces between the dielectric layers and a plurality of external electrodes formed on an outer surface of the multilayer body and electrically connected to the internal electrodes.
With the progress of electronics technology in recent years, miniaturization and capacity enlargement in a multilayer ceramic capacitor are required. To meet these requirements, thinning of a dielectric layer in a multilayer ceramic capacitor has been promoted. However, thinning of a dielectric layer causes a field intensity applied to each layer to be relatively high. Therefore, improvement in reliability during voltage application and particularly in life characteristics presented by a high temperature load test is required with respect to a dielectric ceramic included in a dielectric layer.
An example of a dielectric ceramic constituting a dielectric layer is known from the disclosure of Japanese Patent Publication No. 4-169003. Japanese Patent Publication No. 4-169003 discloses a dielectric ceramic. The dielectric ceramic contains 100 parts of main components including 95.0-98.0 molar % of BaTiO3 having an unreacted BaO content of less than or equal to 0.7 weight % and a Ba/Ti molar ratio of 1.005-1.025, and 2.0-5.0 molar % of rare-earth oxide of at least one type selected from the group consisting of La, Nd, Sm, Dy and Er. The dielectric ceramic contains subcomponents including 0.3-1.5 parts by weight of MnO and 0.5-2.5 parts by weight of oxide glass having BaO—SrO—Li2O—SiO2 as a main component, with respect to the main components.
Japanese Patent Publication No. 4-169003 does not describe the case where the dielectric layers are formed to be thinner. Therefore, when the dielectric ceramic disclosed in Japanese Patent Publication No. 4-169003 is employed as a dielectric layer for a multilayer ceramic capacitor exhibiting the progress of thinning, high reliability during voltage application is not assured.